Biomolecule-functionalized nanowires: from nanosensors to nanocarriers

The unique properties of nanowires offer excellent prospects for designing a new generation of devices and systems exhibiting novel functions. This Review discusses recent scientific accomplishments in the preparation of nanowire-biomaterial hybrids and their potential applications as nanosensors, nanoactuators, and nanocarriers. Nanowires can be readily functionalized with various biochemicals through different linkage chemistries. Such integration of nanowires and biomolecules leads to novel hybrid systems which couple the recognition or catalytic properties of biomaterials with the attractive electronic and structural characteristics of nanowires. Receptor-functionalized nanowires are particularly attractive for direct real-time label-free electrical detection of biomolecular interactions. The unique control over the microstructure of nanowires, and particularly the design of multisegment nanowires, offer spatially defined regions for the defined organization of different biomolecules. This allows the resulting nanowires to perform several tasks simultaneously, and opens the door to a variety of important applications in the areas of nanobioelectronics and nanomedicine. For example, multisegment nanowires designed for nanomedicine applications can couple the selective targeting, therapy, and imaging functions. Such spatially defined anchoring of different biorecognition sites provides also distinct opportunities for the self assembly of nanowires into predetermined designs. The opportunities and challenges involved in designing such nanowire-biomaterial hybrid systems and devices are discussed in the following sections.